Electric furnace.



No. 726,364. PATENTED APR. 28, 1903.

E. A. SJsTBDT.

ELECTRIC PURNACB.

APPLIOATION FILED snm. 2o, 1901,

NO MODEL.

UNITED STATES PATENT OEEICE.

ERNST A. SJSTEDT, OF SAULT STE. MARIE, CANADA, ASSIGNOR TO THE LAKE SUPERIOR POWER COMPANY, OF SAULT STE. MARIE, CANADA.

ELECTRIC FURNACE.

SPECIFICATION forming part of Letters Patent No. 726,364, dated Apr128, 1903. Application led September 20. 1901. Serial No. 75.991. (No model.)

.T0 @ZZ whom, itwtrty concern,.-

Beit known that I, ERNSTADQLF SJsTEDT, of Sault Ste. Marie, in the district of Algoma, in the Province of. Ontario and Dominion of Canada, have invented certain new and useful Improvements in Electric Furnaces; and I do hereby declare that the following is a full, clear, and exact'description of the same.

My invention, which will be hereinafter fully set forth and claimed, relates to an electric furnace for smelting ores.

The object of my invention is an electric furnace forsmelting ores that will withstand fora reasonable time the great heat developed in such appliances, have apertures for the escape of gases of combustion and for tapping the slag and metal, also stoking-holes for breaking up the slag-crusts, and a furnace that has one of its electrodes so placed in the bottom as to be protected and is substituted when burned out by the smelted metal itself.

Figure 1 is atop View of myimproved electric furnace. Fig. 2 is a vertical longitudinal section of the same on line 2 2, Figs. l and 3. Fig. 3 is a vertical transverse sectionY of the same on line 3 3, Figs. l and 2. Fig. 4 is a horizontal section of the samer on the broken line 4 4, Fig. 2.

The furnace-body for convenience sake is' made of rectangular shape. It is constructed of cast-iron sides and ends A and B and a bottom frame C with an interior lining A0130 C0 of refractory material, the bot-tom lining Cobeing retained by a steelplate C', secured to the trame C. D is a cover of refractory material. The refractory material may consist of slabs or bricks o f iire-clay.

The lower parts ot' the sides and ends and the bottom frame are constructed with waterjackets a, b, and c, respectively. The end plates are provided with projecting lugs b b, through which the ends ot stay-bolts B B are passed, secured by nuts, bracing the sides between the ends.

The bottom 'is removable. Registering slotted lugs ct and c' are provided on the lower parts of the sides A and the bottom frame C, respectively, and these receive crossheaded bolts E, resting with their heads e on 'the upper lugs and being provided at the lower ends with mortises e to receive wedges driven in below the lower lugs, as shown in Fig. 8.

The furnace-body is supported atan elevation above the Hoor by legs F to make room for ladle-cars running on rails G.

One of the ends is provided with an openingH for drawing off the slag, said slagnotch H being some distance above the bottom and provided with the customaryspout h.

The iron-notch I, with spout t' for drawing off the metal, is formed within the bottom frame C at the end opposite to that of the slag-notch and below the upper surface ofthe bottom lining.

In the sides A A0 and above the level ofthe slag-notch are vent-holes d, and in the ends are provided Stoke-holes bo, these openings enabling the escape of the gases of combustion and the latter the breaking up the slagcrusts that may form and for facilitating the even settling of the stock.

The. cover D, besides the central opening d for the electrode, has feed-holesd for the introduction of the ore and flux and ventholes d for the escape of gases of combustion.

K and L are respectively the upper and lower-electrodes with connecting-Wires K and L. The upper electrode consists of a battery of square carbon pencilrs,`suitably connected at the top and held adjustably suspended by a suitable mechanical device within the central opening CZ" of the cover D. The bottom electrode L, Vconsisting of a carbon bar, is embedded Within the bottom lining C0 and extends longitudinally from the metalnotch .to the end of t-he bottom frame with which it is in contact. Y In this manner connection is made with the base of the furnace to which the electrode-wire L is attached, and as the carbon is consumed it is substituted by molten metal, which answers the same purpose.-

In starting the furnace when smelting iron ores the upper or pendent electrode K is lowered close to the bottom electrode L, when an arc is drawn, and by feeding the composition of powdered ore and tlux a slag is s oon formed, which acts as an electrode, and thus protects the bottom carbon. As the ore is reduced the metal sinks to the bottom, and as the slag and metal is formed the pendent electrode is gradually raised in accordance With the required volume of current. 'When the slag` reaches near the vent-holes a0, it is drawn off through the slag-notch H, and this operation is repeated until the metal reaches the bottom ot' the slag-notch, When it is tapped out through the metal-notch I into a ladle or direct into sand beds or molds.

I claim as my invention- 1. In an electric smelting-furnace, the combination of a water-jacketed body-case With refractory lining provided With slag-notch, vent-holes and Stoke-holes, a Water-jacketed bottom frame held4 removably on said body and carrying a refractory lining on a plate secured to said frame and having a tappinghole or metal-notch provided in one of the ends, a cover of refractory material having feed and veut holes and opening for the electrode,an upper electrode held adjustably suspended Within said opening of the cover and a bottom electrode embedded in the bottom lining and its ends in contact with the metallic frame of the bottom and Wires connecting the upper electrode and the bottom frame to a suitable electric generator, substantially Y as set forth.

2. In an electric smelting-furuace, the combination of side plates Water-jacketed at the lower parts, end plates Water-jacketed at the lower parts and one of them provided with a slag-notch, lugs on one set of plates, staybolts passing through said lugs and bracing the other set of plates between them, a Water-jacketed bottom frame with bottom plate and metal-notch, slot-ted lugs on said frame and registering lugs on the lower edge of the side plates, cross-headed bolts suspended on the upper lugs and holding up said bottom frame, a cover and lining of the sides, ends and bottom of refractory material, legs supporting said body at a suitable elevation, an electrode embedded in the bottom lining longitudinally from the metal-notch to the end of the bottom frame and in contact With the latter, and an upper electrode adjustably suspended through the cover by suitable mechanical means, substantially as set forth.

In Witness whereof I have hereunto set my hand in the presence or" two witnesses.

' ERNST A. SJOSTEDT.

Witnesses:

FRANK E. LEACH, S. J. HOPKINS. 

